Nonwoven fabrics and method for the production thereof



March 26, 1968 .1. M. EIDGAR, JR 3,375,156

NONWOVEN FABRICS AND METHOD FOR THE PRODUCTION THEREOF Filed May 15, 1963 INVENTOR JAMES M. EDGAR,JR.

ATTORNEY United States Patent 3,375,156 NONWOVEN FABRICS AND METHOD FOR THE PRODUCTION THEREOF James Macmillan Edgar, (in, Wilmington, Del., assiguor to E. I. du. Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed May 15, 1963, Ser. No. 280,691 9 Claims. (Cl. 162-132) This invention relates to nonwoven fabrics having a high degree of bulk and good thermal insulating'proper ties andto a process for their production. More particularly, it relates to high bulk, drapable, lightweight nonwovens for use as insulating interlining fabrics.

Nonwoven interliningmaterials have been used-in thepast to provide bulk-and thermal insulation in garments. Generally, battings of reprocessed wool or 'otherfibers have been used in those applications where bulk and insulation are required but where the interlining need not impart shape and body to the garment, e.g., in'bed jackets, bathrobes,bedspreads, and the like. By their very nature, such battings have very little strength andmust be quilted between two fabrics, one of which provides support and the other of which prevents fiber leakage and assists in maintaining the integrity of the batting during use. The quilting step complicates the fabrication of such materials and increases their cost. Moreover, although the quilting operation imparts some stability to the batting, the interlinings tend to become non-uniform and lumpy after repeated use and laundering due to the shifting and bunching of the loose fibers.

Such nonwoven interlinings are, moreover, unsatisfactory for use in styled outer wear, since the interlining not only must have sufficient strength and stretch to be formed during the garment fabrication but also must pro vide shape and body as well as bulk and insulation to the garment. Thus, in these uses, woven reprocessed wool blankets are commonly used, thewoven fabric providing sufiicient strength and bias stretch to be used in developing the style in the final garment. However, such fabrics are generally of heavy basis weight, for example, about 8 oz./yd. in order to provide the required bulk and insulating properties. Moreover, they lack washability and are therefore not suitable for use-in washwear outer garments. Foam laminates have also been used as interlining materials and provide warmth at a light weight together with satisfactory washability, but they frequently lack drape and flexibility with the result that garments lined therewith tend to be stiff and boardy.

An object of the present invention is to provide a high bulk, coherent nonwoven fabric having good insulating properties.

A more specific object of this invention is to provide a'high bulk, insulating nonwoven interlining material' which is lightweight, drapable, breathable and washable.

A further object of this invention is to provide a high bulk, nonwoven interlining suitable for styled outerwear garments.

operations.

These and other objects of this invention 'will' become apparent in the course of the following'specification and claims.

In accordance with the invention a highbulk laminated fabric is produced by a method comprising the steps of (a) forming a fibrous body by arranginginsuperposed relationship a plurality of nonwoven webs composed of synthetic polymer fibers, the-fibers of a first web of said body being capable of spontaneously elongating .by at least 3% in length more than the fibers'of an adjacent web, and (b) fusing said body into a coherent integral fabric of densified andessentially undensified portions by applying mechanical pressure thereto in a predetermined pattern of intersecting lineal regions. defining enclosed geometrical shapes, while simultaneously heating said body to spontaneously elongate the fibers of said first web by at'least 3% in length more than the fibers of said adjacent web.

The product of the invention is thus a coherent, high bulklaminated fabric comprising two or more superposed nonwoven webs which are individually composed of synthetic polymer fibers adhered at multiple fiber cross-over points throughout each web, said webs being self-bonded toone'another in a plurality of densified intersecting lineal regions defining enclosed essentially undensified geometrical shapes, one'of said webs exhibiting substantially greater surface area in said enclosed geometrical shapes than an adjacent web.

In forming the products of the invention the application of mechanical pressure, e.g. by embossing rolls, to the assembled body of nonwoven webs is preferably conducted in such a manner as to simultaneously accomplish three functions. In the first place it must weld the several webs together by fusion and densification in the areas of the intersecting lineal regions in order to achieve a coherent integral fabric. the same time it should effect within the geometrically shaped portions of the body bounded by the densified intersecting lineal regions an area expansion of the web or webs containing spontaneously elongatable fibers, e.g. to provide a multiplicity of puffed portions giving rise to the bulky nature of the product. Desirably, the embossing step is designed to perform an additional function; namely, to achieve in the individual webs fiber-to-fib'er adherence at multiple fiber cross-over points. Preferablyv such adherence is accomplished by the inclusion in the webs of fibrids, as defined The presence of such a web, which thus remains generally smooth andlevel, acts to direct the buckling of one or more adjacent outer expandable webs away from-the major plane of the initially arranged fibrous body so as to materially assist in increasing thebulk of the structure. Since the individual layers ofthe final product contain fibers which are adhered at their cross-over points, the high bulk laminated fabric is stable such that there is no tendency for individual fibers to shift and bunch together. The high degree of bulk obtainable by expanding the elongatable fibers between the densified lineal regions permits the production of interlining materials having equivalent thickness and thermal insulating properties at a much lower basis weight than those of the prior art. Significantly the structures so obtained have the necessary drape, breathabi1ity, and washability characteristics to permit their use in the fabrication of highly styled outerwear, includingwash-wear garments.

The nonwoven, high bulk= laminated fabrics of the present invention are preferably made from synthetic fiber webs prepared on conventional paper-making equip ment and utilizing fibrids, as defined in' more detail here inafter, to adhere the fibers at their cross-over points.

the spontaneously elongatable fibers are capable of undergoing elongation upon heating at a temperature 30 C. above the second order transition temperature of the fibers for minutes. Although it is possible for the fibers of each of the nonwoven webs in the initially formed fibrous body to be capable of undergoing at least some degree of expansion at the same or different elevated temperatures, it is necessary that the fibers of at least one of the webs be capable of spontaneously elongating by at least 3% in length more than the fibers of'an adjacent web if the entire body is heated to an appropriate temperature. Preferably the web or webs which remain smooth and generally flat in the final product are composed of fibers which are essentially incapable of significant spontaneous elongation at any temperature below their melting point.

Typical spontaneously elongatable synthetic polymer fibers suitable for use in the invention are described in Belgian Patent 566,145, granted Sept. 27, 1958, and in US. Patent 2,952,879. Many of these fibers may be prepared to be capable of elongating spontaneously up to 30% or more beyond their own initial length upon heating to a temperature 30 C. above their second order transition temperature. It will be apparent that in producing the products of the invention, higher bulk values can advantageously be obtained by selecting fibers which elongate to a greater extent. Particularly suitable synthetic polymers for preparing spontaneously elongatable fibers are polyesters, such as polyethylene terephthalate, polyhexahydrop-xylylene terephthalate, and similar polymers of monomers prepared by reacting terephthalic acid with ethylene glycol or similar glycols. Polyamides are also useful for this purpose, particularly poly(p-xylylene azelaicamide). In addition to these, other spontaneously elongatable fibers include those composed of polyurethanes, acrylonitrile polymers and the like. Polyolefins such as polypropylene and other addition type polymers may also be used.

The term fibrid is employed herein to designate a non-rigid, wholly synthetic polymeric particle capable of forming paper-like structures. Thus to be designated a fibrid, a particle must possess (a) an ability to form a waterleaf having a couched wet tenacity of at least about 0.002 gram per denier when a plurality of the said particles is deposited from a liquid suspension upon a screen, which waterleaf, when dried at a temperature below about 50 C., has a dry tenacity at least equal to its couched wet tenacity and (b) an ability, when a plurality of the said particles is deposited concomitantly with staple fibers from a liquid suspension upon a screen, to bond a substantial weight of the said fibers by physical entwinement of the said particles with the said fibers to give a composite waterleaf with a wet tenacity of at least about 0.002 gram per denier. In addition, fibrid particles have a Canadian freeness number between 90* and 790 and a high absorptive capacity for water, retaining at least 2.0 grams of water per gram of particle under a compression load of about 39 grams per square centimeter.

Any normally solid wholly synthetic polymeric material may be employed in the production of fibrids. By normally solid is meant that the material is non-fluid under normal room conditions. By an ability to bond a substantial weight of. (staple) fibers is meant that at least 50% by weight of staple based on total staple and fibrids can be bonded from a concomitantly deposited mixture of staple and fibrids.

It is believed that the fibrid characteristics recited above are a result of the combination of the morphology and non-rigid properties of the particle. The morphology is such that the particle is non-granular and has at least one dimension of minor magnitude relative to its largest dimension, i.e., the fibrid particle is fiber-like or film-like. Usually, in any mass of fibrids, the individual fibrid particles are not identical in shape and may include both fiber-like and film-like structures. The non-rigid characteristic of the fibrid, which renders it extremely supple in liquid suspension and which permits the physical entwinement described above, is presumably due to the presence of the minor dimension. Expressing this dimension in terms of denier, as determined in accordance with the fiber coarseness test described in Tappi 41, lA-7A, No. 6 (June) 1958, fibrids have a denier no greater than about 15.

Complete dimensions and ranges of dimensions of such heterogeneous and odd-shaped structures are difficult to express. Even screening classifications are not always completely satisfactory to define limitations upon size since at times the individual particles become entangled with one another or wrap around the wire meshes of the screen and thereby fail to pass through the screen. Such behavior is encountered particularly in the case of fibrids made from soft (i.e., initial modulus below 0.9) polymers. As a general rule however, fibrid particles, when classified according to the Clark Classification Test (Tappi 33, 2948, No. 6 (June) 1950) are retained to the extent of not over 10% on a 10-mesh screen, and retained to the extent of at least on a 200-mesh screen.

Fibrid particles are usually frazzled, have a high specific surface area, and \as indicated, a high absorptive capacity for water.

Preferred fibrids are those the waterleaves of which when dried for a period of twelve hours at a temperature below the stick temperature of the polymer from which they are made (i.e., the minimum temperature at which a sample of the polymer leaves a wet molten trail as it is stroked with a moderate pressure across the smooth surface of a heated block) have a tenacity of at least about 0.005 g.p.d.

The preparation of nonwoven materials from fibrids and stable-fibers is described in detail in US. 2,999,788, issued Sept. 12, 1961.

The major weight proportion of fibers in the Web or webs -to undergo area expansion in the final product should be'spontaneously elongatable fibers as above defined. Such webs, in addition to containing an adherent, e.g., a fibrid for elfecting fiber to fiber adherance at multiple cross-over points, may also contain minor amounts of other fibrous materials although it is preferred that these be kept at a minimum in order to achieve the most desirable properties in the products. Thus, ordinary staple fibers of synthetic organic polymers such as any of the polyamides, polyesters, polyurethanes, acrylic fibers, and polyolefins or cellulosic fibers such as rayon, cellulose acetate and the like, may be used in minor amounts. In addition, certain natural fibers such as goat hair, cotton, wool and the like may also be used in minor amounts. A preferred composition comprises spontaneously elongatable polyester fibers and copolyester fibrids as an adherent.

The Web or webs which are not intended to undergo area expansion may be formed from any appropriate adherent such as above described fibrids and any wholly synthetic polymer fiber. The basic polymer which comprises the essentially non-elongatable fibers can be the same as those described above with reference to the spontaneous elongatable fibers. Mixtures of synthetic fibers may also be used in these webs and such mixtures may include minor amounts of cellulosic or natural fibers such as previously discussed. A preferred composition comprises essentially non-elongatable polyester fibers and a copolyester fibrid 'binder.

The elongatable and essentially non-elongatable fibers used in the present invention may be in the form of either staple fiber or continuous filament. The initial webs made from these fibers may be formed by any conventional means such as by using a conventional carding device, a Rando Webber, or paper-making equipment. The fibers may be adhered to one another in the webs by any suitable means. While fibrids are preferably used to adhere the fibers in these webs, other means can also be used. Typical among such other methods is the salt bonding F process described in U.S. Patent 2,869,973 which utilizes a hydrotropic salt in conjunction with a solvent having a boiling point below the temperature at which elongation of the spontaneously elongatable fibers occurs.

When fibrids are used as the adherent, at least about 1% of the initial web should be fibrids. The amount of adherent used, in general, will affect the nature of the final product. In those webs containing elongatable fibers, the amount of adherent should be adjusted to provide a coherent web without drastically restricting the freedom of the fibers to elongate between the points of adherence. Generally, fibrid contents within the range of about 1 to about 50% are satisfactory, while those in the range of about 5 to about 35% are preferred. In those webs containing non-elongatable fibers, the range may be variedmore widely depending on the final structure desired. Generally, it is preferred to use fibrid contents ranging from about 1 to about 35%. I

The extent of bulk which is developed from a single web is dependent on the choice of spontaneously elongatable fibers therein, i.e., the extent to which they are capable of elongating, the fibrid content of the web insofar as it may affect the freedom of the fibers to elongate, the size of the grid openings in the embossing means and, of course, on the basis weight of the web.

The embossing temperature and pressure should be sufiicient to fuse the fibrids in the individual webs at least in the areas contacted by the grid elements, thereby bonding the layers together in those areas. Fusing temperatures will, of course, be determined by the melting points of the fibrous components in the sheet structure. In general, the fusion temperature should 'be at least about 30 C. below the melting temperature of the polymer used in the preparation of the staple fiber or continuous filament component. For many composite sheets containing polyester, polyamide or acrylic polymer fibrids, fusion temperatures between 180 C. and 230 C. are preferred. Further, the

embossing temperature should be sufiicient to expand the fibers in the web or webs containing the spontaneously elongatable fibers.

It will be apparent that the invention offers a wide variety of styling possibilities depending upon such factors as the design or pattern formed by the densified intersecting lineal regions, the extent to which the spontaneously elongatable fibers in one or more webs will expand in comparison with the one or more essentially non-elongatable webs, the basis weight of the fabrics, and the relative arrangement or location of different types of webs in the laminated fabrics. Still other means can be employed for imparting special aesthetic qualities or functional properties to the fabrics, e.g., by dyeing, waterproofing or otherwise finishing the fabrics, and by laminating or combining the fabrics with other nonwoven or Woven fabrics, films etc. A number of means for effecting such styling variations will now be described in greaterdetail.

The bonding of the various nonwoven webs together may be accomplished by the use of any suitable heated embossing rolls, plates and the like. The grid pattern of the embossing means may be of any suitable design, i.e., having raised portions which densify and bond in a predetermined pattern of intersecting lineal regions which define diamond, square, rectangular, circular or other geometrical shaped openings. The spacing between individual grid elements or portions is not critical although the essentially undensified areas defined thereby should be large enough to permit the web or webs containing elongatable fibers to expand freely beyond the grid surface and to buckle away from the web of nonelongating fibers. Throughout the length and width dimensions of the products of this invention, the areas formed by direct bonding of the two or more webs together should be only a fraction, e.g. 20% or less, of the areas in which no interweb bonding is effected. I

With respect to the relative arrangement of the various webs in the final fabric, a preferred embodiment involves resulting hand sheet is dried in an air oven at 110 C a structure wherein an intermediate non-area expanded web is positioned between two or more webs each composed of fibers which have been elongated to provide a greater surface area. The presence of the interior web,

step to provide a structure of very high bulk. A plan view showing the quilt-like patterned surface of such a struc ture as well as the cross-sectional configuration is shown in FIGURE 1.

In another embodiment, one, two or more webs comprising spontaneously elongatable fibers are positioned adjacent one side of a web containing essentially nonelongatable fibers to provide, upon embossing, a struc ture having one smooth, planar side and one quilted or puffed side. A plan view of such a structure containing two area expanded webs opposite one side of a nonarea expanded web is shown in FIGURE 2.

By way of comparison, FIGURE 3 illustrates a plan view of a single layer nonwoven web having a basis weight equivalent to the structures shown in FIGURES 1 and 2 but lacking the bulk thereof.

The following examples illustrate the invention. Unless otherwise indicated, all parts and percentages are on a weight basis both therein and elsewhere in the specification.

Example I This examples illustrates the preparation of a multilayer, high bulk nonwoven structure having a smooth, planar side and a quilted or puffed side.

Fibrids are prepared from a copolyester of by weight ethylene terephthalate recurring units and 20% ethylene isophthalate recurring units as described in U.S. Fatent 2,999,7 88 by adding 40 parts by Weight of a solutron containing 20% by weight of the copolyester in dimethylformamide in an even stream to 400 parts by weight of an ice cold mixture of 92.5 parts dimethylformamide and 7.5 parts water in a Waring Blendor operating at approximately 14,000 rpm. This process (shear precipitation) leads to copolyester fibrids which are filtered and washed with water until free of organic liquids.

A fibrid and fiber aqueous slurry (about 0.01% solids content) is then prepared having a fibrous content of 80 parts by weight of conventional, non-elongatable 4 inch, 1.5 denier per filament polyethylene terephthalate staple fibers and 20 parts by weight of the above described fibrids. A waterleaf having a basis weight of 1.0 oz./yd. is prepared from this slurry using a conventional papermakers hand sheet mold with a mesh screen. The

and is found to be about 0.015 inch thick.

Two additional, separate waterleaves are then prepared III the manner described above using as the staple; component 2.5 denier per filament, inch, self-elongatable polyethylene terephthalate fibers prepared by the techniques of Example III of U.S. Patent 2,952,879 to have an ability to spontaneously elongate about 8%. The

waterleaves are separately dried in an air oven at C i and each has a basis weight of 1.0 oz./yd. and a thickness of about 0.015 inch.

A layered fibrous is then formed by superposing the two sheets containing self-elongatable fibers on the sheet containing conventional staple fibers. The assembly is then laid between stainless steel embossing plates and embossed at a pressure of 200 lbs/sq. in. on the grid and a temperature of 210 C. for 2 minutes. The embossing plates have opposed matching faces comprising a grid-like surface arranged in a diamond pattern, there being a distance of 1 inch between opposite vertices of each diamond.

In the embossing step the fibrids in each of the three layers are fused. Fusion of the fibrids beneath the grid elements of the embossing plate thereby bonds the three layers into a unitary structure, the bonded and densified regions corresponding to the diamond-shaped pattern of the embossing plates, Simultaneously with the bonding of the three layers together, the self-elongatable fibers in the layers containing these fibers are caused to elongate by the temperature of the embossing operation. Since each of these layers is a coherent sheet, each layer expands as a unit within the confines of each diamond shaped portion of the embossing grid. The expansion or putiing out of these outer layers proceeds in the direction away from the inner sheet containing the non-elongatable fibers.

The resulting structure is removed from the embossing plates and is found to consist of a unitary coherent structure having one planar, smooth side and one puffed or quilted side. FIGURE 2 shows a cross-section of the resulting structure. From that illustration it can be seen that although the three layers remain generally distinct from one anOther and are separated by air spaces in those areas where expansion has taken place, they are nevertheless integrally bonded together between such areas to provide integrity to the overall structure. The resulting structure has a total basis weight of 3 oz./yd. and a maximum thickness of 0.14 inch. In contrast, a single sheet prepared from polyester staple fibers and copolyester fibrids at a basis weight of 3 oz./yd. has a thickness of only 0.046 inch when heated in the absence of pressure to fuse the fibrids as illustrated in FIGURE 3. Further, the structure produced by the process of this invention has adequate thermal insulation properties at a light weight and is drapable, breathable and washable, making it particularly suited for styled outerwear garments especially of the wash-wear type.

Example II This example illustrates the production of a high bulk, nonwoven structure having a smooth interior layer and quilt-like, puffed outer layers.

A l oz./yd. nonwoven web is prepared from conventional non-elongatable polyester staple fibers (1.5 d.p.f., inch) and copolyester fibrids by the procedure described in Example 1. Twoadditional nonwoven webs, each having a basis weight of l oz./yd. are then prepared from the spontaneously elongatable fibers and copolyester fibrids described in Example I. The web containing nonelongatable fibers is sandwiched between the webs containing elongatable fibers and the layered assembly is embossed using the procedure of Example 1.

During the embossing step the fibrids are fused and the three layers are bonded together at regular spaced apart intervals corresponding to the diamond-shaped pattern of the embossing grid to produce a unitary structure. At the same time, the outer layers containing spontaneously elongatable fibers expand and buckle away from the interior layer in the regions bounded by the grid elements of the embossing plates. The structure of the resultant fabric, after removal from the embossing plates, is shown in FIGURE 1. The fabric has a basis weight of 3 oz./yd. and a maximum thickness of 0.26 inch. Its thickness is more than 5 /2 times that of a comparable 3 oz./yd. sheet prepared from polyester fibers and copolyester fibrids by conventional papermaking techniques (FIGURE 3) and is approximately double that of the equivalent basis weight structure prepared according to Example I. The final structure has thermal insulating properties approximately equivalent to those of an 8 oz./yd. reprocessed wool blanket at less than /2 the weight of the wool blanket, as shown in the table below.

THERMAL PROPERTIES 1 Calories/second/cublc centimeter] 0.

Finally, the structure is drapable, breathable and washable, making it highly suitable for use as an interlining, particularly for wash-wear outer garments.

In the foregoing examples, thickness is measured with a low pressure thickness gauge (Custom Scientific Instruments, Inc., Arlington, N.I.). The sample is suspended vertically between the presser foot and anvil of the thickness gauge during testing to eliminate compression of the fabric under its own weight. The presser foot of the gauge has an area of 1 square centimeter and the gauge exerts a pressure of essentially zero on the sample during testing. Each sample is preconditioned at 130il0 F. for a minimum of 2 hours and then at 65% R.I-I., 70 F. for a minimum of 16 hours before testing. The reported thickness is the average thickness in inches of fiber samples.

Thermal conductivity is determined by using a radiant heat source (Infrared lamp-375W, in reflectorgooseneck type holder) to maintain a standard temperature of C. on one side of the test sample and then measuring the temperature at the other side of the sample using a radiation thermopile (Central Scientific Co., Ceno design 6.5 cm. sq. collecting apertureCat. No. 81070) and a potentiometer (Leeds and Northrup Model 8667). The time rate of heat transfer in calories per second per cubic centimeter per degree Centigrade is reported. This value is proportional to the rate of heat transfer at a constant temperature drop across the material.

The products of the present invention are particularly suited for those uses requiring a lightweight interlining material having high bulk and good thermal insulating properties. Such uses include interlining materials for bed jackets, bedspreads, bathrobes, certain skirts, and the like. Because they have sufiicient strength to be shaped and styled and retain their integrity after repeated use and washing, they are especially suited for use as thermal insulating interlinings in outerwear garments, such as jackets and coats, particularly those of the wash-wear type.

Many equivalent modifications will be apparent to those skilled in the art from a reading of the above without a departure from the inventive concept.

I claim:

1. Method for producing a high bulk laminated fabric comprising the steps of a) providing at least one waterleaf (I) comprising synthetic polymer fibers,

(b) providing at least one waterleaf (II) comprising spontaneously elongatable synthetic polymer fibers selected from the group consisting of polyesters, polyamides, polyurethanes, and polyolefins,

each of said waterleaves (I) and (II) being separately prepared by depositing an aqueous slurry onto a papermaking screen, the fibers of waterleaf (II) being spontaneously elongatable by at least 3% in length more than the fibers of waterleaf (I),

(c) forming a fibrous body by arranging said waterleaves (I) and (II) in a superposed relationship, and

(d) fusing said body into a coherent integral fabric of densified and essentially undensified portions by applying mechanical pressure thereto in a predetermined pattern of intersecting lineal regions defining enclosed geometrical shapes large enough to permit said waterleaf (II) containing spontaneously elongatable fibers to expand freely beyond the confines of the said pattern and to buckle away from said waterleaf (I) not containing spontaneously elongatable fibers, while simultaneously heating said body to spontaneously elongate fibers of said waterleaf (II) by at least 3% in length more than the fibers of said waterleaf (I).

2. Method of claim 1 wherein a major weight proportion of the fibers of said waterleaf (II) are spontaneously elongatable.

3. Method of claim 1 wherein said pattern of intersecting lineal regions defines a quilted pattern in said fabric.

4. Method of claim 1 wherein said body comprises three 9 said waterleaves (I) and (II), two outer waterleaves (II) containing fibers spontaneously elongatable by at least 3% in length more than the fibers of the intermediate waterleaf (I).

5. Method of claim 1 wherein said body comprises three said waterleaves (I) and (II), two of said waterleaves (II) being disposed opposite one face of said waterleaf (I) and containing fibers spontaneously elongatable by at least 3% in length more than the fibers of said waterleaf (I).

6. Method for producing a high bulk laminated fabric comprising the steps of (a) providing at least one waterleaf (I) comprising synthetic polymer fibers and synthetic polymer fibrids,

(b) providing at least one waterleaf (II) comprising spontaneously elongatable synthetic polymer fibers selected from the group consisting of polyesters, polyamides, polyurethanes, and polyolefins, and synthetic polymer fibrids,

each of said waterleaves (I) and (II) being separately prepared by depositing an aqueous slurry onto a papermaking screen, the fibers of waterleaf (II) being spontaneously elongatable by at least 3% in length more than the fibers of waterleaf (I),

(c) forming a fibrous body by arranging said waterleaves (I) and (II) in a superposed relationship, and

(d) fusing said body into a coherent integral fabric of densified and essentially undensified portions by applying mechanical pressure thereto in a predetermined pattern of intersecting lineal regions defining enclosed geometrical shapes large enough to permit said waterleaf (II) containing spontaneously elongatable fibers to expand freely beyond the confines of the said pattern and to buckle away from said waterleaf (I) not containing spontaneously elongatable fibers, while simultaneously heating said body to spontaneously elongate fibers of said waterleaf (II) by at least 3% in length more than the fibers of said waterleaf (I).

7. Method of claim 6 wherein the said waterleaves (I) and (II) each contain between about 1 and by weight of fibrids.

8. Method of claim 6 wherein the said waterleaves (I) and (II) each contain between about 5 and 35% by weight of fibrids.

9. Method of claim 7 wherein the fibers of each of said waterleaves (I) and (II) are composed of polyethylene terephthalate and wherein the fibrids are composed of a copolyester of ethylene terephthalate units and 20% ethylene isophthalate units.

References Cited UNITED STATES PATENTS 2,621,139 12/1952 Messing l56-220 X 2,978,006 4/1961 Clemens 161127 X 2,987,101 6/1961 Luker 162-146 X 2,999,788 9/1961 Morgan 162146 3,032,465 5/1962 Selke et al. 162146 3,097,127 7/1963 Ostmann 162-146 MORRIS SUSSMAN, Primary Examiner. 

1. METHOD FOR PRODUCING A HIGH BULK LAMINATED FABRIC COMPRISING THE STEPS OF (A) PROVIDING AT LEAST ONE WATERLEAF (I) COMPRISING SYNTHETIC POLYMER FIBERS, (B) PROVIDING AT LEAST ONE WATERLEAF (II) COMPRISING SPONTANEOUSLY ELONGATABLE SYNTHETIC POLYMER FIBERS SELECTED FROM THE GROUP CONSISTING OF POLYESTERS, POLYAMIDES, POLYURETHANES, AND POLYOLEFINS, EACH OF SAID WATERLEAVES (I) AND (II) BEING SEPARATELY PREPARED BY DEPOSITING AN AQUEOUS SLURRY ONTO A PAPERMAKING SCREEN, THE FIBERS OF WATERLEAF (II) BEING SPONTANEOUSLY ELONGATABLE BY AT LEAST 3% IN LENGTH MORE THAN THE FIBERS OF WATERLEAF (I), (C) FORMING A FIBROUS BODY BY ARRANGING SAID WATERLEAVES (I) AND (II) IN A SUPERPOSED RELATIONSHIP, AND (D) FUSING SAID BODY INTO A COHERENT INTEGRAL FABRIC OF DENSIFIED AND ESSENTIALLY UNDENSIFIED PORTIONS BY APPLYING MECHANICAL LPRESSURE THERETO IN A PREDETERMINED PATTERN OF INTERSECTING LINEAL REGIONS DEFINING ENCLOSED GEOMETRICAL SHAPES LARGE ENOUGH TO PERMIT SAID WATERLEAF (II) CONTAINING SPONTANEOUSLY ELONGATABLE FIBERS TO EXPAND FREELY BEYOND THE CONFINES OF THE SAID PATTERN AND TO BUCKLE AWAY FROM SAID WATERLEAF (I) NOT CONTAINING SPONTANEOUSLY ELONGATABLE FIBERS, WHILE SIMULTANEOUSLY HEATING SAID BODY TO SPONTANEOUSLY ELONGATE FIBERS OF SAID WATERLEAF (II) BY AT LEAST 3% IN LENGTH MORE THAN THE FIBERS OF SAID WATERLEAF (I). 